Gear, A.S. [publisher]. THE NATIONAL BANK NOTE DETECTER, THE ONLY INFALLIBLE SYSTEM OF DETECTING COUNTERFEIT AND ALTERED BANK NOTES AND FRACTIONAL CURRENCY. COMPLETE IN NINE RULES, EXPLAINED AND ILLUSTRATED BY ENGRAVINGS, SCIENTIFICALLY ARRANGED FOR SELF-INSTRUCTION, APPLICABLE TO ALL NOTES ISSUED BY ANY BANK IN THE UNITED STATES. New Haven, 1866. Fourth edition. 16mo [16 by 10.5 cm], original grained brick-red cloth; sides decoratively paneled in blind; upper cover lettered in gilt. 81, (1) pages, including 16 full-page woodcut engravings of a simulated bank note, eight of which depict the appearance of genuine design elements, the other eight illustrating counterfeit design elements. Near fine. Very rare. Not in the Newman, Bass, or Fuld Library sales; the Champa Library had an 1868 edition only. Only two copies of this edition have come to market in recent years: this (for which John J. Ford, Jr. paid $150 in 1963) and the Stack Family Library copy, which is in a lovely, but not original, binding. Gear's treatise was a predecessor of Laban Heath's ubiquitous publications on the topic, from which, as Eric Newman notes, Heath "adopted many of his concepts and expressions." The illustrations are not finely produced for the reason stated in the introduction: "These engravings are executed in a coarse manner, that the difference between the counterfeit and genuine may be more easily distinguished." A June 23, 1866 testimonial letter from C.E. Twombley, Paying Teller, U.S. Treasury, is reproduced on page 81, recommending it "to the public as an invaluable book for every business man." Priced at $1.00 versus $1.50 for the Heath work, its major competitor, Gear downplays the main difference between the two works: "We might fill the book with specimens of genuine work, which would increase the cost of the same only, without being of any aid to the learner. Genuine bank notes are always at hand, and can be examined by all at any time." Ex John J. Ford, Jr. library (lot 497); ex Kolbe & Fanning's 2012 New York Book Auction, lot 284.